REGULATION - ADDITIONAL INFORMATION (Details) - USD ($) $ in Thousands						3 Months Ended	9 Months Ended
	Jun. 28, 2023	Jun. 01, 2023	Apr. 12, 2023	Mar. 30, 2023	Feb. 22, 2023	May 31, 2023	Jun. 30, 2023	Sep. 30, 2022
Schedule of Regulatory Filings [Line Items]
Regulatory assets							$ 528,114	$ 500,666
NJNG
Schedule of Regulatory Filings [Line Items]
Regulatory assets							522,858	495,300
Interim rate increase (decrease), amount				$ 28,200
Approved rate increase (decrease), amount				31,400
NJNG | COVID-19 Pandemic
Schedule of Regulatory Filings [Line Items]
Regulatory assets							$ 3,900	$ 6,900
Base Rate Stipulation
Schedule of Regulatory Filings [Line Items]
Weighted average cost of capital							6.84%
Approved return on equity							9.60%
BGSS | NJNG
Schedule of Regulatory Filings [Line Items]
Requested rate increase (decrease), amount		$ (38,600)	$ 81,900
BGSS | NJNG
Schedule of Regulatory Filings [Line Items]
Interim rate increase (decrease), amount					$ (29,900)	$ (32,400)
BPU | NJNG
Schedule of Regulatory Filings [Line Items]
Approved rate increase (decrease), amount				$ 3,200
Annual recovery increase	$ 740
BGSS Balancing | NJNG
Schedule of Regulatory Filings [Line Items]
Requested rate increase (decrease), amount		(7,400)	9,000
Conservation Incentive Program | NJNG
Schedule of Regulatory Filings [Line Items]
Requested rate increase (decrease), amount		27,500	10,200
RAC
Schedule of Regulatory Filings [Line Items]
Interim rate increase (decrease), amount			3,700
NJCEP
Schedule of Regulatory Filings [Line Items]
Interim rate increase (decrease), amount			$ (900)
SAVEGREEN
Schedule of Regulatory Filings [Line Items]
Annual recovery increase		$ 10,700